Dietary fat and appetite control in obese subjects: weak effects on satiation and satiety

The present study assessed the capacity of both high fat and high carbohydrate (CHO) foods to lead to overconsumption in 12 obese women (mean BMI = 42 kg/m2). Subjects were provided with either a low (527 kcal) or high (985 kcal) energy meal at midday. Energy intake was then measured in a later ad libitum dinner meal in which subjects ate from a range of either high fat or high CHO foods. Energy intake following exposure to these meals was then assessed using food intake diary records which were kept for the rest of the day and for the following 24 h. The energy manipulations at lunch gave rise to different levels in the rated intensity of hunger. At the dinner meal subjects consumed an average of 937 kcal following the high energy lunch and 1026 kcal following the low energy lunch (an increase of 10%). However, average intake from the high CHO dinner meal was only 677 kcal compared to 1336 kcal from the high fat dinner meal (an increase of 97%). Consequently the most important variable influencing dinner meal size was not level of hunger but the nutrient content of the range of foods consumed. Analysis of dinner meal intake revealed a significant interaction between lunch meal size and dinner meal type. This means that when hunger level was high subjects over-ate on the high fat but not the high CHO foods. Average post-dinner intakes following the high fat and high CHO meals did not differ significantly.(ABSTRACT TRUNCATED AT 250 WORDS)